Private
The security phrase to the package will be, "Open in the name of Salazar and Helga." I'll include a map of how to find my estate from the air.
No apology needed, young sir. I never thought it was an intentional slight. Personally, I've found that what works for me is somewhat more formal than a face-to-face conversation, because there is no undercurrent of tone of voice or change of posture to modify your actual words, but much less formal than a written letter. The better you know someone, the more liberties you can take, because they've heard your actual spoken words before. When in doubt, I've always tried to err on the side of politeness, which is what a gentleman should always try to do anyway.